Distribution patterns of most of the 20 Neotropical freshwater turtles belonging to the family Chelidae are usually based on few locality records. We here report on vouchered records of three species of the chelid genus Mesoclemmys in the Brazilian state of Mato Grosso. Presence of M. vanderhaegei is confirmed for the Amazon River Basin, and M. gibba and M. raniceps are recorded in Mato Grosso for the first time.

Adaptive plasticity has been postulated as one of the integrating factors that explain the distribution and abundance of species on different habitat with different environmental variations. The environmental heterogeneity is the most important factor for the maintenance, increment or decrement of biodiversity. On this study we determined the effect of periodicity and habitat structure on the richness and composition of species of three different habitat: stream (P1), temporary ponds (P2) and permanent dam (P3) in an agrosystem in the Central Brazilian Cerrado. We performed nine excursions to the field during November 2005 to April 2007. We found and registered the species by direct search and vocalization orientation. We identified 19 anuran species belonging to four families: Bufonidae (one species), Hylidae (nine species), Leptodactylidae (five species), and Leiuperidae (four species). The greatest richness and abundance were recorded in temporary ponds (P2), which differed significantly from the stream (P1) and from the permanent dam (P3). Dendropsophus nanus, Hypsiboas raniceps and Leptodactylus chaquensis showed strong association with P2. P2 and P3 showed greater differentiation between themselves in species composition than when compared to P1. Despite the fact that the studied areas are surrounded by intense farming and present a high degree of anthropic disturbance, these areas showed a high species richness being an important refugee for the amphibians, although the species found on this work are usually associated to impacted areas or open phytophysiognomies and are favored with the creation of artificial environments such as those in this study.

New locality records and distribution map for the recently described Elachistocleis magnus are here presented. Originally described from Rondônia state, western Brazil (Amazonia), E. magnus was until now recorded for only two additional localities in the same state. The new records presented herein, which considerably enlarge the known range of the species, include three additional Brazilian states – Amazonas, Pará, and Mato Grosso (including records in the Brazilian Cerrado). We provide color description of the species in life, and discuss variation in habitats used by this species.

Se provee información sobre un individuo de Amphisbaena alba (Reptilia: Squamata) que reconoce y usa un sendero de la hormiga cortadora de hojas Atta laevigata (Hymenoptera: Formicidae) en la sabana neotropical de Brasil. También registramos y describimos movimientos de desviación de obstáculos y el comportamiento de A. alba para reconocer el sendero de hormigas. Adicionalmente, discutimos cómo el mimetismo químico de A. alba pudiera estar involucrado en nuestra observación y sugerimos que esta relación va más allá de un simple inquilinismo, donde A. alba puede usar el nido como un sitio de reposo y alimentación para otros organismos asociados con nidos de hormigas cortadoras.

O Cerrado brasileiro é considerado um <em>hotspots</em> de biodiversidade e apresenta um ritmo acelerado de perda de hábitat. Este trabalho objetivou realizar análises citogenéticas em duas espécies do Cerrado mato-grossense L<em>eptodactylus chaquensis</em> e <em>Hypsiboas raniceps</em>. Para <em>L chaquensis</em> foi encontrado número cromossômico de 2n=22 com morfologia 2K=16M+4SM+2ST. A NOR foi observada no par cromossômico oito. Para <em>H. raniceps </em>foi observado número cromossômico de 2n=24 com morfologia 2K=12M+8SM+4ST. A NOR esteve localizada no braço longo do par 11. Foi observado uma variação interpopulacional na posição de uma terceira NOR, localizada na região terminal de um dos homólogos do par cromossômico 4 (população A) e próxima ao centrômero do braço longo de um dos homólogos do par cromossômico 1 (população C). Os dados aqui observados diferem dos encontrados na literatura para estas duas espécies, demonstrando a importância de se realizar análises citogenéticas com a fauna da região.